// Displays changes in temperature from data in an input file.

import java.io.*;    // for File
import java.util.*;  // for Scanner

public class Temperatures {
   public static void main(String[] args) throws FileNotFoundException {
      Scanner input = new Scanner(new File("weather.txt"));
      double prev = input.nextDouble();  // fencepost
      while (input.hasNext()) {
         if (input.hasNextDouble()) {
            double next = input.nextDouble();
            System.out.println(prev + " to " + next +
               ", change = " + (next - prev));
            prev = next;
         } else {
            input.next();  // throw away unwanted token
         }
      }
   }
}